We collated available evidence of breeding and conservation problems for the Japanese Murrelet in the Izu Islands, Japan. After species description in 1835, it was first collected in the Izu Islands in 1877, with breeding first noted in 1901. Over the 20th century, murrelets were found breeding at 11 islands (i. e., Udonejima, Niijima, Shikinejima, Hanshima, Kozushima, Onbasejima, Tadanaejima, Sanbondake, Motone, Kojine, and Torishima) and were not thought to breed at 7 islands (i. e., Oshima, Toshima, Jinaijima, Miyakejima, Mikurajima, Hachijojima, and Hachijokojima). Surveys have not been conducted at 7 islands (i. e., Zenisu, Inanbajima, Aogashima, Beyoneizu-Retsugan, Myojinsho, Sumisujima, and Sofugan). The population is centered in the northern Izu Islands between Udonejima and Sanbondake. Once considered the world stronghold for the species, a large population decline apparently occurred in the mid-late 20th century: a) breeding no longer occurs at Shikinejima and Kozushima; b) some breeding habitat has been lost at Sanbondake; c) large numbers of nests reported by egg harvesters at Udonejima, Hanshima, and Sanbondake in early century no longer occur; and d) murrelets were observed less frequently on ferry trips between Oshima and Niijima in 1990-95 than in 1983-89. Current breeding population size appears to range between 350-850 breeding pairs (-7-43% of the global population estimated between 4, 000-10, 000 birds or 2, 000-5, 000 pairs). Major colonies occur at Tadanaejima (100-300 pairs), Onbasejima (75-150 pairs), and Sanbondake (75-100 pairs), plus 20-30 pairs at Kojine. Another 100-300 pairs may nest at other islands (i. e., Udonejima, Niijima, Hanshima, and Torishima) where recent estimates are not available. Conservation issues include: human settlement; past egg harvesting; recreational surf fishing at remote islands; predation by introduced predators; habitat loss due to post-war bombing of Sanbondake; habitat destruction due to human activities; habitat loss due to volcanic eruptions; relatively high levels of predation by crows, snakes, and falcons; and mortality in commercial gill nets. Additional surveys, monitoring, and assessment of conservation issues are urgently needed in Izu Islands for this rarest species of the family Alcidae which is endemic to Japan.
The Long-billed Murrelet (Brachyramphus perdix) is one of the rarest and most poorly understood alcids in Asia. First described by Pallas in 1811 as Cepphus perdix (the Partridge Murrelet), their solitary nesting at inland sites in remote areas of eastern Siberia and northern Japan has limited studies of their habitat preferences and population status. Because of this paucity of information, we were concerned whether viable populations would continue to persist in the southern portion of its breeding range in the face of a variety of conservation issues. Therefore, we compiled historical and recent at-sea and inland records of Long-billed Murrelets in Japan during the breeding and winter seasons. We also conducted inland, from-shore and at-sea surveys in northeastern Hokkaido between 1996 and 2001. Few murrelets were recorded during these surveys and based on historic information, murrelets may have been extirpated from some areas where they may have bred historically (e. g., northern Honshu and eastern Hokkaido). We discuss the conservation problems, including gill-net fishing, logging of mature forests in coastal regions, oil pollution, and predation, that may have led to its extirpation from some areas of Japan during the breeding season.
The historic and present status of seabirds in Hokkaido is summarized, based on published and unpublished data. At least 12 species breed in Hokkaido. The breeding pairs of seabirds in recent years in Hokkaido are estimated as follows: Common Murre (Uria aalge) <10; Tufted Puffin (Lunda cirrhata) 15; Spectacled Guillemot (Cepphus carbo) 100; Ancient Murrelet (Synthliboramphus antiquus) <20; Rhinoceros Auklet (Cerorhinca monocerata) 300, 000; Slaty-backed Gull (Larus schistisagus) 10, 000; Black-tailed Gull (Larus crassirostris) 30, 000; Red-faced Cormorant (Phalacrocorax urile) 25; Japanese Cormorant (Phalacrocorax capillatus) 3, 000; Pelagic Cormorant (Phalacrocorax pelagicus) 10; Streaked Shearwater (Calonectris leucomelas) 120; Leach's Stormpetrel (Oceanodroma leucorhoa) 900, 000. The present status of the Long-billed Murrelet (Brachyramphus perdix) is unclear. The colony size of Common Murre shrank with annual decreasing rate of 12.2% (1938-80)-26.6% (1981-94) on Teuri Island. It has decreased 24.8% annually, and it has not been observed on Moyururi Island since 1985. The Tufted Puffin and Spectacled Guillemot decreased 9-15% annually during the last 30 years. The Slaty-backed Gull increased 11.0% annually (1963-95) on Teuri Island, and 8.5% annually (1972-93) on Yururi Island. Black-tailed Gull increased by 5% annually (1987-2000) on Rishiri Island, but decreased on Teuri Island during the 1990's. The Japanese Cormorants increased by 5-9% annually on Teuri and Yururi Islands. Its number increased at annual rate of 6.4% during 1959-86, but decreased at annual rate of 10.4% during 1987-96 on Moyururi Island. At 12 of the 14 surveyed colonies predation by gulls and/or crows were reported, and disturbances caused by introduced rats and cats was reported at five colonies. Although most of the colonies are legally protected, few conservation programs have been effectively conducted. Seabird mortality by fishing nets was reported around six colonies, but protective measure for seabirds has not been taken. We here propose, therefore, non-fishing sea areas for seabird protection around such breeding islands.
To estimate the breeding population of Streaked Shearwaters (Calonectris leucomelas) on Sasudo Island, Jejudo, Korea, quadrat surveys were conducted during the hatching period in 1998, the early rearing period in 1999 and the early incubation period in 2000. In 2000, burrow density was 0.15/m2±0.02 (mean±SE). Burrow density was high in the abandoned field, rocky area and take off site of the birds in the island, where 71.3% of 595 burrows were occupied. The breeding population was estimated to be 7, 486±3, 000 pairs (mean±SE). Only 36.4% and 19.8% of burrows were occupied in 1998 (n=353) and 1999 (n=140), respectively. Burrow occupancy seemed to decrease through the breeding stages. Breeding failures were recorded in 31 out of 54 burrows (57.4%) in 7-29 August 1999. Predation by Norway Rats (Rattus norvegicus) was possibly the cause of mortality of eggs or chicks in 26 of these 31 unsuccessful burrows. Norway Rat predation may be the main factor affecting the breeding success of Streaked Shearwaters on the island.
It has long been believed that the Ryukyu Bush Warbler Cettia diphone riukiuensis (Kuroda, 1925) is resident and the only subspecies distributed in Ryukyu Archipelago, Japan. However, we found that Bush Warblers on Okinawajima occur in two distinct plumage forms. One form, the brown form, is characterized by having deep rusty brown upper parts, while the other, gray form, has grayish olive upper parts. Our investigations, using mist-nets to trap birds clarified that the brown form is resident and that the gray form winters on the Island. Univariate analysis of 13 measurements taken of the birds, revealed significant morphological differences of the two forms. Likewise, multivariate analysis differentiated the brown form from the gray form. The type series of C. d. riukiuensis (14 specimens, already lost) were identified as being of the gray form by using a linear discriminant function obtained from 4 measurements from the two forms. The measurements and plumage characteristics in the original description of C. d. riukiuensis conform with the gray form. These results indicate that the gray form should be ascribed to C. d. riukiuensis. It has become clear that C. d. riukiuensis is a wintering bird, not a resident on Okinawajima. The measurements and plumage characteristics of the brown form conform with the original description of the Borodino Bush Warbler C. d. restricta (Kuroda, 1923). The type series of C. d. restricta (2 specimens, already lost) were identified as being the same as the brown form by using linear discriminant function. These results indicate that the brown form should be attributed to C. d. restricta. C. d. restricta has been regarded as an extinct, endemic subspecies that occurred only on Minami-Daitojima Island. Our results suggest, however, that C. d. restricta is not extinct and that it inhabits on Okinawajima.
Habitat selection and flock size of Tibetan Partridge (Perdix hodgsoniae) were investigated in Lhasa mountains, Tibet, from November 1995 to February 1996. The habitats constituted the study area were divided into seven types. Partridge flocks used all the seven types of habitat in late-autumn to early-winter. However, during late-winter the birds were only found in three types of habitat on the south-facing slopes or open fields. Stream belts with scrub dominated by Rose Rosa sericea and Barberry Berberis hemleyana were the most preferable throughout autumn-winter. Food availability was considered to be a main factor affecting habitat selection. Partridges performed day-roosting behavior around mid day under dense bushes in the stream belts. Their night-roosting sites were mostly located under dense scrub vegetation on the ground at higher altitudes, especially habitats on the north-facing slopes. As the season progressed, frequencies of encountering partridge flocks decreased from 0.78 in late-autumn to early-winter to 0.37 per h in late-winter, with change of mean flock size from 7.41 to 5.21.
Diurnal activity budgets of Mallard (Anas platyrhynchos) wintering at the Hattabara dam lake in Hiroshima prefecture, western Japan, were investigated during November 2000 to March 2001. Mallards spent 67.9, 16.0 and 14.7% of the time resting, preening, and locomoting, respectively. Less than 1% of the time was spent for each of feeding, alert, agonistic and courtship activities. Activity patterns varied among the months, apparently in response to declining water levels and human disturbances. Resting was the primary activity of Mallards throughout winter. Time spent on resting was highest (P<0.05) during the mid day and evening, while the time spent on locomotion and courtship was highest during the morning (P<0.05). Mallards used a site near the dam for resting during the day. The site was off limits to boaters and sport fisherman. During the night, they used the shallow areas for feeding because these areas were inaccessible during the daytime due to human disturbances. The shallow feeding areas dried up from December to January when water level decreased sharply. Mallards responded by leaving the dam lake at dusk to feed in the adjacent ponds during this period. More than 95% of the area of these ponds was covered by 2-3m tall Common Reeds (Pharagmites australis) and was inaccessible to the Mallards. Appropriate management of the ponds may improve Hattabara dam lake as a waterfowl habitat.
This paper reports a modification of the chromodomain helicase DNA binding protein (CHD) method for sex identification in the Japanese Crested Ibis, Nipponia nippon. In this modification, we employed a restriction enzyme, MboII, instead of HaeIII that was used in the original method. The use of MboII gave similar results to those found with HaeIII. The reliability of the modified method was confirmed by applying both methods to adult ibises of known sex and also by sequencing amplified nucleotides from adult birds and chicks. We used the modified method to sex three chicks obtained from a pair of Japanese Crested Ibises from China that was presented by the Chinese government. In addition, we have shown that the embryonic tissue, mainly blood vessels, left in the eggshell after hatch can be a good source of DNA for sexing.
Neophorn had musculus pectoralis major profundus, reflecting its soaring flight, while Spilornis lacked this layer of the pectoralis, showing general (non-soaring) flight type. The pars anterior of m. latissimus dorsi in Spilornis was so anteriorly shifted as to connect the shoulder and the base of the neck. The complicated feature of the linkage of tendon of m. ambiens to tibial muscles, in Spilornis, was shown. General pattern of branchial musclature of Neophron was illustrated.